What Rifle Do You Shoot?
Prescribing a load for a rifle without knowing which caliber and model it is...well, is like prescribing medicene for an unknown ailment.
Different makers often rely on different rates of rifling twist...and even if several folks buy the same model rifle from the same maker, it's not uncommon to experience a .001" to .002" difference in actrual bore diameter. Some times it takes a great deal of experiementing to settle on an optimum load for any rifle.
I shoot mostly Knights (4 of them), but also shoot T/Cs (2 of them), and own and shoot at least a half dozen other varrying brands/models. Lots of shooting has determined exact loads for each.
Generally speaking, if the rifle you shoot has a turn-in-28 inch twist bore, a saboted 240- to 275-grain bullet will give you best accuracy. If the rifle has a snappier turn-in-24 inch twist bore (i.e. Savage 10MLII), a slightly longer and heavier saboted 300 grain bullet is very often the way to go when seeking best accuracy.
Sabot-Bullet fit with the bore is important for accuracy. If you were to purchase, say, the easy loading flat-based 250-grain Barnes T-EZ bullets for your rifle, and found they loaded extremely too easy...there's a good chance that you may never know how well the rifle shoots. It takes a good grip of the rifling by the sabot in order to properly transfer the spin of the rifling to the bullet riding inside the sabot.
My favorite saboted whitetail bullet has been the 260-grain Harvester Muzzleloading "Scorpion PT Gold". Out of most .50 caliber rifles, it loads with just enough compression and grip of the rifling for excellent accuracy. However, in several of my ".50" caliber rifles, which have .502" bores, it loads way too easily - and accuracy suffers. However, Harvester offers this bullet packaged with either their standard black .50x.45 Crush Rib Sabot...or a slightly tighter fitting red .50x.45 Crush Rib sabot. And with the tighter fitting red sabot, those rifles with slightly over-sized bores are tack drivers.
My load is generally 110-grains of Blackhorn 209, which gets this 260-grain polymer-tipped spire point out of the muzzle at 2,030 f.p.s. - with right at 2,380 f.p.e. At 100 yards, it hits with about 1,550 f.p.e., and at 200 yards with about 1,100 f.p.e. For deer-sized game, 800 f.p.e. is generally considered the minimum needed. One good buck I took at 191 yards with this load, shot from a Knight "Long Range Hunter", ran just 30 yards and rolled in the snow like a big cottontail.
Just my two cents worth.